Science against Old Age
How to accelerate evolution and be forever young
Maxim Skulachev, Forbes, 11.01.2018
There are animals that can be called evolutionary champions. They just turned off aging and can keep a young body for life.
In the two previous episodes of our bio-series, I tried to lead the reader to the idea that aging and its crowning death are not some random processes that occur due to the imperfection of the structure of our body, its wear and tear. In my opinion, it is more correct to consider them as the final stage of the individual's development program, embedded, like all other stages, in our genes. In this article I will try to give you the most important argument confirming that this is indeed the case.
Life without old age
To begin with, I will allow myself a small digression. And why would you even need such an unpleasant thing as aging? Well, still – just death. It is necessary for the change of generations. But why on earth has nature rewarded us with a humiliating period of withering of vital functions? Was it really impossible to do without him and just live for yourself – not to grieve and die in one day?
The short answer is that you can do without aging!
It turns out that there are animal species, and among them there are our close relatives – mammals, who have practically no aging. In fact, it seems that there are quite a lot of such species. But only one is being studied in laboratories. Meet the totemic beast of our anti–aging project - the naked digger. In fact, it is a rodent, i.e. a relative of a mouse, about the same size:
So, based on its size, metabolic rate, position in the classification of animals, it would have to live about like a mouse or a rat – 2.3 well, a maximum of 5 years. And he lives... for who knows how long. The experiment has been going on for more than 30 years and the diggers who were captured in Africa more than 30 years ago are still alive. And most importantly, the mortality rate of diggers does not increase with age. That is, that 2-year-olds, that 10-year-olds, that 20-year-old animals celebrate their next birthday with the same probability. That is, they, simply by definition, do not age.
Two reasonable questions arise:
- Why is a naked digger so lucky?
- How in the name of Darwin and Weisman did he do it?!
In this article I will try to answer the first question.
Wise old age
To do this, you will first have to state the point of view that aging is another way to accelerate evolution. The same as sexual reproduction and death (see the first episode of our series). The fact is that the main driving force of evolution – natural selection – is usually much more convenient to work not on young and healthy animals, but on slightly weakened individuals. That is, the elderly. Namely, they are made by aging.
I note that in the wild, the concept of "old man" is very different from our human one. First of all, because animals do not have menopause. That is, no matter how "old" they are, they can still reproduce. Aging also manifests itself in a weakening of the overall functionality of the body and, as a result, increases the likelihood of death.
To illustrate this point, Academician Vladimir Skulachev somehow came up with a special "two-hare theorem". Here it is: imagine two birds with one stone. For simplicity, let's assume that the main factor in the natural selection of these hares is a fox – whether she eats them or not. Now let's assume that one of the hares carries a small (single), but slightly useful mutation in its genes. Well, for example, he is a little bit smarter than the rest of his relatives. But just a little bit - after all, it is extremely unlikely that as a result of one mutation he would immediately become a rabbit Einstein. From the point of view of the development of the species of big-eared carrot lovers, it would be very correct to give some advantage to a smart hare in order to try to consolidate this useful feature in future generations. But how can this be done if the trait is very small and extremely insignificant for natural selection? In other words, both ordinary and "smart" hares are equally good at running away from a fox ("A hare will always run away from a fox, because for him it's a matter of life and death, and for her – lunch," he said Aesop"). But let's start aging in our hares. We will slowly begin to worsen the work of all systems. They start to run slower, it's worse to confuse the tracks, now the heart is playing tricks, and they get sick more often because of a weakened immune system. With such slightly aged hares, the fox at some point already has a good chance to catch up with them and eat them.
By the way, predators actually tend to feed on old and sick animals, not young and healthy ones. From the photo of lions hunting buffaloes, it can be seen that if predators tried to attack a herd of young animals, the balance of forces would not be at all in favor of lions.
But in relation to a smart hare, such chances of "being eaten" will appear later, because at first his "intelligence" will allow him to run away from the fox, even despite the general weakening from aging. For example, he is slightly better at confusing tracks or detecting a predator earlier. As a result, there is a period, and quite a long one, since aging is slow, when a small advantage in the speed of information processing will save his life. All this time they will not eat him, but ordinary hares. As a result, the smart one will have time to breed hares a couple more times and, as a result, the next generation of this species will be "enriched" with smarter hares. And this will happen solely due to aging, which allowed natural selection to "pull out from under the noise" and fix small signs that are invisible against the background of young and healthy individuals.
Evolutionary exception
Why did I need this lengthy digression about hares? Why is it important to understand that aging is a tool that accelerates evolution? Because it allows us to formulate an important hypothesis:
Actually, not all species need to evolve so quickly.
There are animals that can be called evolutionary champions. These are creatures that have invented (of course, as a result of evolution) something that has allowed them to adapt amazingly to environmental conditions and continue to change them - only to spoil. Very rarely, but such examples can be found. The hypothesis is that such species can afford... not to age.
The naked digger mentioned above is such a champion. Do not look at the fact that he is small, as if puny (not at all, as it turned out), and scary.
In fact, in front of you is a great inventor, cooler than us humans. The fact is that the digger is the only eusocial mammal. You and I are quasi–social. That is, if it gets really hot, we can survive as a couple on a desert island. But the digger is not. They live like social insects – ants, termites and bees – in colonies with a clear division of duties and professions. And this is the only way they can exist.
The colony is headed by the Queen Mother. She has her husband, the Crown Prince, with her. Either one, or there are up to 3 of them, scientists have not yet figured out here. A colony can number from a couple dozen to several hundred subjects of the queen. And most of them are her children. Only the queen can reproduce. The rest are guards, soldiers, workers, foragers, nannies, etc. They live underground in very hard ground in East Africa. With such a matriarchal system, only the queen and her husband (husbands) matter for evolution. Because only they bring offspring, i.e. they pass their genes to the next generation. The rest of the colony is the maintenance staff. It is clear that with such a device, the royal couple has no special problems with adapting to the environment. They are fed, protected, and have comfortable rooms in the center of the maze. Whatever happens there, on the surface, they don't really need to adapt to anything. So you can afford, for example, to evolve in some more relaxed mode. And for this, it would be worth disabling some particularly "troublesome" mechanisms for accelerating evolution - for example, aging.
And the digger really turned off his aging. This is best seen in the graph of the dependence of the mortality of diggers on age. Her (addiction) was calculated based on the results of an epic experiment conducted by an American zoologist for 25 years Rachel Buffenstein. In her 2005 article, Figure number 5 shows this graph:
Mortality of naked diggers depending on age
See – it's a horizontal line! That is, the probability of death for diggers at any age ... is the same! With you and me, and with any other aging animals, this probability increases exponentially (see the graph below). But the diggers don't.
Mortality of people depending on age according to
federal State Statistics Service for 2010
The death schedule of the diggers made a lot of noise in the scientific community 12 years ago. Everyone rushed to study these animals and have already learned quite a lot about them. It turned out that these are real supermen-supermaus. They practically do not feel pain, their brain withstands abnormally long oxygen starvation, and with age, bones do not thin and joints do not suffer, and in general, most of their senile diseases are either simply not detected or extremely rare.
The same applies to the amazing resistance of diggers to cancer. For a long time, scientists simply could not detect a single case of cancer in them. Moreover, some mechanisms of this resistance to cancer have also been discovered – for example, the cells of a naked digger have a particularly strong so-called "contact inhibition of growth". That is, when cells, like cancer cells, begin to divide uncontrollably, they very quickly come into contact with their neighbors. So, the fact of such contact for the digger cells leads to a very strict ban on further division.
In fairness, I must say that in the end, after a pathomorphological analysis of 1200 corpses of naked diggers, it was still possible to detect a couple of cases of cancerous tumors. But if such an analysis were carried out with laboratory mice, cancer would be found in almost 100% of animals. This also applies to humans: about a third of deceased people have cancerous formations. That is, the digger is hundreds of times more resistant to cancer compared to us!
Photo MSU
I suspect that the question has already begun to torment you, but how did the naked digger manage to turn off his aging (see the second question at the beginning of the article)? It seems that our scientific group has figured it out, which I will tell you about in the next column of my series. Follow the sequel!
In conclusion, let me remind you that the digger was able to afford to "turn off" the sad circumstances associated with aging, simply because he no longer needs to accelerate evolution. And here I would like to draw your enlightened attention to the fact that Homo Sapiens is also such an "evolutionary champion". In the ability to adapt to the environment, we surpassed even naked diggers. Because we use not evolution with its snail's pace of evolution, but technological progress for this.
If we want to live further north, we don't grow fur, but invent clothes. If we do not have enough food, we do not increase our gastrointestinal tract to digest grass, but create agriculture. That is, we fully deserve the title of "champions". But we have gained independence from evolution only recently – only a few thousand years ago. And the digger – several million. Therefore, maybe we just haven't had time to get rid of such a small evolutionary dirty trick as aging yet? It seems that this is indeed the case and I will try to prove it in the next series.
Another important question will also be raised there – is it possible to cancel aging in humans not to wait a million years for the evolution of the species Homo Sapiens, but to apply our favorite technique – technological progress?
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